In recent years, hybrid vehicles are receiving widespread attention as environmentally friendly vehicles. As motive power sources, the hybrid vehicles incorporate, in addition to a conventional engine, a power storage apparatus, an inverter, and a motor driven by the inverter.
Among such hybrid vehicles, the vehicles capable of traveling while switching between a traveling mode where traveling is performed only by the motor without starting the engine (hereinafter also referred to as “EV mode”) and a traveling mode where traveling is performed by both the engine and the motor (hereinafter also referred to as “HV mode”) are known.
For example, Japanese Patent Laying-Open No. 2001-112112 discloses a hybrid vehicle that switches between such traveling modes in accordance with an operation point of a driveshaft. The hybrid vehicle travels in EV mode when started. Thereafter, when the operation point of the driveshaft crosses the border between an underdrive range and an overdrive range, and enters the overdrive range, underdrive coupling is switched to overdrive coupling. The engine is started, and traveling is performed in HV mode.
However, with the hybrid vehicle disclosed by Japanese Patent Laying-Open No. 2001-112112, the driver cannot recognize in advance the timing for switching from EV mode to HV mode, and therefore, the driver may feel discomfort about the abrupt starting of the engine.
In particular, it is expected that the driver is likely to feel such discomfort with a hybrid vehicle in which a power storage apparatus is chargeable from a power supply external to the vehicle (such as from a system power supply). That is, the hybrid vehicle having an externally charging function is equipped with a power storage apparatus that is greater in power storage capacity than that of a conventional hybrid vehicle (without the externally charging function), so as to make full use of charging from the external power supply. Then, the kilometer per charge of EV mode having conventionally been, for example, some kilometers, will be increased to be not smaller than 10 kilometers. Thus, traveling would be performed mostly in EV mode. Accordingly, the driver is likely to feel discomfort when EV mode is switched to HV mode.
Additionally, if a traveling mode switching point can be indicated to the driver who wishes to continue traveling in EV mode, the driver can intentionally avoid switching from EV mode to HV mode. Accordingly, environmentally friendly driving can be achieved.